IEC TS 62903:2018
(Main)Ultrasonics - Measurements of electroacoustical parameters and acoustic output power of spherically curved transducers using the self-reciprocity method
Ultrasonics - Measurements of electroacoustical parameters and acoustic output power of spherically curved transducers using the self-reciprocity method
IEC TS 62903:2018, which is a Technical Specification,
a) establishes the free-field convergent spherical wave self-reciprocity method for ultrasonic transducer calibration,
b) establishes the measurement conditions and experimental procedure required to determine the transducer's electroacoustic parameters and acoustic output power using the self-reciprocity method,
c) establishes the criteria for checking the reciprocity of these transducers and the linear range of the focused field, and
d) provides guiding information for the assessment of the overall measurement uncertainties for radiation conductance.
This document is applicable to:
i) circular spherically curved concave focusing transducers without a centric hole working in the linear amplitude range,
ii) measurements in the frequency range 0,5 MHz to 15 MHz, and
iii) acoustic pressure amplitudes in the focused field within the linear amplitude range.
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Overview - IEC TS 62903:2018 (Ultrasonics, self‑reciprocity method)
IEC TS 62903:2018 is a Technical Specification from the IEC that defines the free‑field convergent spherical wave self‑reciprocity method for calibration and measurement of spherically curved ultrasonic transducers. It specifies the measurement conditions and experimental procedures to determine electroacoustical parameters and acoustic output power, sets criteria for reciprocity and linearity of the focused field, and gives guidance for assessing measurement uncertainty (radiation conductance). The document applies to circular, concave spherically curved focusing transducers (no centric hole), operating in the 0.5 MHz to 15 MHz frequency range and within the linear amplitude range of the focused field.
Key topics and technical requirements
- Measurement method: Free‑field self‑reciprocity calibration for spherically curved transducers.
- Applicable transducers: Circular spherically curved concave focusing transducers without a centric hole, linear amplitude operation.
- Frequency & amplitude: 0.5 MHz to 15 MHz; acoustic pressure amplitudes within the linear range.
- Required apparatus and setup: specifications for water tank, fixturing/positioning systems, reflectors, current monitor (probe), oscilloscope and measurement hydrophone.
- Geometric and beam parameters: measurement of effective half‑aperture, beamwidth, focus half‑angle and effective area.
- Calibration outputs: transmitting response (to current/voltage), voltage sensitivity, pulse‑echo sensitivity, radiation conductance, acoustic output power, mechanical Q, and electroacoustic efficiency.
- Diffraction & propagation: treatment of diffraction correction coefficients and guidance on speed of sound and attenuation in water.
- Reciprocity and linearity checks: criteria to verify transducer reciprocity and the focused field linear range.
- Uncertainty evaluation: informative annex with Type A/B uncertainty components and combined standard uncertainty for radiation conductance.
Applications and who uses this standard
IEC TS 62903:2018 is aimed at practitioners requiring traceable, repeatable ultrasonic transducer calibration and output power measurement:
- Calibration and metrology laboratories performing hydrophone and transducer calibration.
- Ultrasonic transducer manufacturers validating electroacoustical performance.
- Medical ultrasound device developers needing focused‑field power and sensitivity data.
- Nondestructive testing (NDT) labs and research institutions characterizing focused transducers for imaging or therapy.
- Engineers and quality teams implementing calibration procedures, uncertainty budgets, and compliance testing for focused ultrasonic sources.
Related standards (if applicable)
Refer to other international standards and IEC publications on ultrasonics, hydrophone calibration, acoustic power measurement and measurement uncertainty for complementary requirements and normative references. These provide broader context for traceability and conformity in ultrasonic metrology.
Standards Content (Sample)
IEC TS 62903 ®
Edition 1.0 2018-01
TECHNICAL
SPECIFICATION
Ultrasonics – Measurements of electroacoustical parameters and acoustic
output power of spherically curved transducers using the self-reciprocity
method
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IEC TS 62903 ®
Edition 1.0 2018-01
TECHNICAL
SPECIFICATION
Ultrasonics – Measurements of electroacoustical parameters and acoustic
output power of spherically curved transducers using the self-reciprocity
method
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.140.50 ISBN 978-2-8322-5026-6
– 2 – IEC TS 62903:2018 IEC 2018
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Symbols . 12
5 General . 13
6 Requirements of the measurement system . 14
6.1 Apparatus configuration . 14
6.2 Measurement water tank . 14
6.3 Fixturing, positioning and orientation systems . 14
6.4 Reflector . 14
6.5 Current monitor (probe) . 14
6.6 Oscilloscope . 15
6.7 Measurement hydrophone . 15
7 Measurement of the effective half-aperture of the spherically curved transducer . 15
7.1 Setup . 15
7.2 Alignment and positioning of the hydrophone in the field . 15
7.3 Measurements of the beamwidth and the effective half-aperture . 15
7.4 Calculations of the focus half-angle and the effective area . 16
8 Measurements of the electroacoustical parameters and the acoustic output power . 16
8.1 Self-reciprocity method for transducer calibration . 16
8.1.1 Experimental procedures . 16
8.1.2 Criterion for checking the linearity of the focused field . 16
8.1.3 Criterion for checking the reciprocity of the transducer . 16
8.2 Calculations of the transmitting response to current (voltage) and voltage
sensitivity . 17
8.3 Calculations of the transmitting response at geometric focus to current
(voltage) . 17
8.4 Calculation of the pulse-echo sensitivity level . 18
8.5 Measurements of the radiation conductance and the mechanical quality
factor Q . 18
m
8.5.1 Calculations of the acoustic output power and the radiation
conductance . 18
8.5.2 Measurement of the frequency response of the radiation conductance . 18
8.6 Measurement of the electroacoustic efficiency . 18
8.6.1 Calculation of the electric input power . 18
8.6.2 Calculation of the electroacoustic efficiency . 18
8.7 Measurement of the electric impedance (admittance) . 19
9 Measurement uncertainty . 19
Annex A (informative) Relation of the average amplitude reflection coefficient on a
plane interface of water-stainless steel and the focus half-angle for a normally
incident beam of a circular spherically curved transducer [1, 2] . 20
Annex B (informative) Diffraction correction coefficient G in the free-field self-
sf
reciprocity calibration method for circular spherically curved transducers in water
neglecting attenuation [2, 3, 4]. 24
Annex C (informative) Calculation of the diffraction correction coefficient G (R/λ,β) in
sf
the free-field self-reciprocity calibration in a non-attenuating medium for a circular
spherically curved transducer [2, 3, 4, 7] . 26
Annex D (informative) Speed of sound and attenuation in water. 28
D.1 General . 28
D.2 Speed of sound for propagation in water . 28
D.3 Acoustic attenuation coefficient for propagation in water . 28
Annex E (informative) Principle of reciprocity calibration for spherically curved
transducers [2, 3, 4]. 29
E.1 Principle of reciprocity calibration for an ideal spherically focused field of a
transducer . 29
E.2 Principle of reciprocity calibration of a real spherically focused field of a
transducer . 30
E.3 Self-reciprocity calibration of a spherically curved transducer . 30
Annex F (informative) Experimental arrangements . 35
F.1 Experimental arrangement for determining the effective radius of a
transducer [2, 3, 4, 13] . 35
F.2 Experimental arrangement of the self-reciprocity calibration method for a
spherically curved transducer [2, 3, 4, 13] . 35
Annex G (informative) Relationships between the electroacoustical parameters used
in this application [13] . 37
G.1 Relations between the free-field transmitting response to voltage (current)
and the voltage sensitivity with the radiation conductance . 37
G.2 Relation of the radiation conductance and the electroacoustic efficiency . 38
G.3 Relation of the transmitting response and voltage and acoustic output power . 38
G.4 Relation of the pulse echo sensitivity and the radiation conductance . 38
Annex H (informative) Evaluation and expression of uncertainty in the measurements
of the radiation conductance . 39
H.1 Executive standard . 39
H.2 Evaluation of uncertainty in the measurement of the radiation conductance . 39
H.2.1 Mathematical expression . 39
H.2.2 Type A evaluation of standard uncertainty . 40
H.2.3 Type B evaluation of standard uncertainty . 40
H.2.4 Evaluation of the combined standard uncertainty for the radiation
conductance . 42
Bibliography . 46
Figure A.1 – Relation curve of the amplitude reflection coefficient r(θ ) on the interface
i
of water-stainless steel for a plane wave with the incident angle θ . 22
i
Figure A.2 – Average amplitude reflection coefficient r (β) on the plane interface of
av
water-stainless steel in the geometric focal plane of a spherically curved transducer vs.
the focus half-angle β . 23
Figure C.1 – Geometry of the concave radiating surface A of a spherically curved
transducer and its virtual image surface A′ for their symmetry of mirror-images about
the geometric focal plane (x,y,0) . 26
Figure E.1 – Spherical coordinates . 31
Figure E.2 Function G (kasinθ), diffraction pattern F (kasinθ) and F (kasinθ) in the
a 0 0
geometric focal plane [7] . 32
Figure F.1 – Scheme of the measurement apparatus for determining the effective half-
aperture of a transducer . 35
– 4 – IEC TS 62903:2018 IEC 2018
Figure F.2 – Scheme of free-field self-reciprocity method applied to a spherically
curved transducer . 36
Table A.1 – Parameters used in calculation of the average amplitude reflection
coefficient . 21
Table A.2 – Amplitude reflection coefficient r(θ ) on a plane interface of water-stainless
i
steel for plane wave vs. the incident angle θ . 21
i
Table A.3 – Average amplitude reflection coefficient r (β) on plane interface of
av
water-stainless steel in the geometric focal plane of a spherically curved transducer vs.
the focus half-angle β . 22
Table B.1 – Diffraction correction coefficients G of a circular spherically curved
sf
transducer in the self-reciprocity calibration method [2, 3, 4] . 24
Table D.1 – Dependence of speed of sound in water on temperature [5] . 28
Table E.1 – G values dependent on kasinθ for β ≤ 45° where x = kasinθ (according to
a
O'Neil [7]) . 32
Table E.2 – The (R/λ) values dependent on β when θ ≥ θ and β < 45° for G
min max Ga a
= 0,94; 0,95; 0,96; 0,97; 0,98; 0,99 . 33
Table H.1 – Type B evaluation of the standard uncertainties (SU) of input quantities in
measurement . 41
Table H.2 – Components of the standard uncertainty for the measurement of the
radiation conductance using the self-reciprocity method . 44
Table.H.3 – The measurement results and evaluated data of uncertainty for five
transducers . 45
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ULTRASONICS – MEASUREMENTS OF ELECTROACOUSTICAL
PARAMETERS AND ACOUSTIC OUTPUT POWER OF SPHERICALLY
CURVED TRANSDUCERS USING THE SELF-RECIPROCITY METHOD
FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In
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specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62903, which is a Technical Specification, has been prepared by IEC technical
committee 87: Ultrasonics.
– 6 – IEC TS 62903:2018 IEC 2018
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
87/652/DTS 87/659/RVDTS
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
• terms defined in Clause 3: in bold type.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
INTRODUCTION
An ultrasonic transducer is an important acoustic device that can act as a transmitter or a
receiver in the applications of medical ultrasound, non-destructive testing, and ultrasonic
materials processing. The performance of a transducer is a decisive factor that governs the
device's range of applicability, efficiency and quality control in the manufacturing. The
mechanisms, transmitting fields, performances, and measurement methods used for these
transducers have been studied over the past few decades. However, the electroacoustical
characterization and measurement methods applied for spherically curved transducers have
not been defined in standard documents for either terms or protocols.
This document defines the relevant electroacoustical parameters for these devices and
establishes the self-reciprocity measurement method for spherically curved concave focusing
transducers.
– 8 – IEC TS 62903:2018 IEC 2018
ULTRASONICS – MEASUREMENTS OF ELECTROACOUSTICAL
PARAMETERS AND ACOUSTIC OUTPUT POWER OF SPHERICALLY
CURVED TRANSDUCERS USING THE SELF-RECIPROCITY METHOD
1 Scope
This document, which is a Technical Specification,
a) establishes the free-field convergent spherical wave self-reciprocity method for ultrasonic
transducer calibration,
b) establishes the measurement conditions and experimental procedure required to
determine the transducer's electroacoustic parameters and acoustic output power using
the self-reciprocity method,
c) establishes the criteria for checking the reciprocity of these transducers and the linear
range of the focused field, and
d) provides guiding information for the assessment of the overall measurement uncertainties
for radiation conductance.
This document is applicable to:
i) circular spherically curved concave focusing transducers without a centric hole working in
the linear amplitude range,
ii) measurements in the frequency range 0,5 MHz to 15 MHz, and
iii) acoustic pressure amplitudes in the focused field within the linear amplitude range.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60050-801:1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-801:1994
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
p
av
average acoustic pressure
acoustic pressure averaged over the effective area of the transducer
Note 1 to entry: Average acoustic pressure is expressed in pascals (Pa).
3.2
r (β)
av
average amplitude reflection coefficient
ratio of the free-field echo average acoustic pressure p (β) reflected by the reflector on the
av
geometric focal plane over the space area coincident with the effective area of the
spherically curved transducer of focus half-angle β, if the transducer were removed, to the
reference acoustic pressure p on the effective area of the transducer in a non-attenuation
medium with negligible diffraction, r (β) = p (β)/p
av av 0
3.3
G
sf
diffraction correction coefficient
ratio of the average acoustic pressure over the spherical segment surface of the spherically
curved transducer's virtual image at a position in the distance of twice geometric focal
length from the transducer, if an ideal reflecting mirror were located on the geometric focal
plane, to the reference acoustic pressure of the transducer in the free-field of a non-
attenuation medium
3.4
A
effective area
area of the radiating surface of a theoretically predicted transducer with specific
field distribution characteristics that are approximately the same as those of a real transducer
of the same type
Note 1 to entry: For a spherically curved transducer, the theoretically predicted acoustic pressure distribution on
the geometric focal plane of a transducer should be approximately the same as that of the real transducer with the
same geometric focal length when operating at the same frequency.
Note 2 to entry: The half-aperture of an effective area is also named the effective half-aperture or the effective
radius.
Note 3 to entry: The effective area of a transducer is expressed in metres squared (m ).
3.5
η
a/e
electroacoustic efficiency
ratio of the acoustic output power to the electric input power
3.6
electroacoustical reciprocity principle
electroacoustical reciprocity theorem
principle that the ratio of the free-field voltage (current) sensitivity of a reciprocal
transducer as a receiver, to the transmitting response to current (voltage) of the
reciprocal transducer as a projector is constant
Note 1 to entry: This principle is independent of the construction of the reciprocal transducer.
3.7
free-field
sound field in a homogeneous isotropic medium whose boundaries exert a negligible effect on
the sound wave
[SOURCE: IEC 61161:2013, 3.2]
– 10 – IEC TS 62903:2018 IEC 2018
3.8
M
free-field voltage sensitivity of a spherically curved transducer
receiving voltage response of a spherically curved transducer
ratio of the open-circuit output voltage of a spherically curved transducer within the field of a
point source at the geometric focus to the free-field acoustic pressure acting on the space
surface where the transducer surface was present, if that transducer were removed
Note 1 to entry: Free-field voltage sensitivity of a spherically curved transducer is expressed in volts per
pascal (V/Pa).
3.9
geometric beam boundary
surface containing straight lines passing through the geometric focus and all points around
the periphery of the transducer aperture
Note 1 to entry: The definition applies to transducers of known construction.
[SOURCE: IEC 61828:2006, 4.2.36]
3.10
F
geo
geometric focal length
distance from the geometric focus to the ultrasonic transducer's focusing surface
Note 1 to entry: The definition applies to transducers with known construction and is equal to the radius of
curvature of the radiating surface.
Note 2 to entry: The focusing surface is the surface of constant phase, whose periphery is coincident with the
transducer's aperture.
Note 3 to entry: Geometric focal length is expressed in metres (m).
3.11
geometric focus
point for which all of the effective path lengths in a specified longitudinal plane are equal
Note 1 to entry: The geometric focus is also the point for which all waves from the transducer have the same
delay as viewed in the approximation of geometrical acoustics neglecting diffraction.
[SOURCE: IEC 61828:2006, 4.2.39, modified – In the definition, the added explanation for the
definition "Also, the point for which all.diffraction." has been moved to a Note to entry.]
3.12
L
Mpe
pulse-echo sensitivity level
ratio of the received open-circuit voltage for the first echo signal of the spherically curved
transducer when acting as a receiver to the exciting voltage of the transducer when it is
transmitting a tone burst ultrasonic beam in a direction perpendicular to an ideal plane
reflector (r = 1) at the geometric focal plane
Note 1 to entry: The ratio is expressed in decibels (dB).
3.13
G
radiation conductance
ratio of the acoustic output power and the squared effective transducer input voltage
Note 1 to entry: It is used to characterize the electrical to acoustical transfer of ultrasonic transducers.
Note 2 to entry: The frequency of the input voltage (or current) should be noted.
Note 3 to entry: Radiation conductance is expressed in siemens (S).
[SOURCE: IEC 61161:2013, 3.8, modified – In the definition, "RMS" has been replaced with
"effective".]
3.14
reciprocal transducer
linear, passive and reversible transducer
Note 1 to entry: An example of a non-reciprocal transducer is one that mixes a magnetic field device with an
electric field device.
[SOURCE: IEC 60565:2006, 3.24]
3.15
J
reciprocity parameter
ratio of the free-field voltage sensitivity of a transducer as a receiver to the
transmitting response to the current of the transducer as a projector, or the ratio of the
free-field current sensitivity of a transducer as a receiver to the transmitting response to
the voltage of the transducer as a projector
Note 1 to entry: The reciprocity parameter of a spherically curved transducer, J = J , is equal to the quotient of
sf
twice the effective area of the transducer divided by the acoustic characteristic impedance of the medium, i.e.
J = 2A/(ρ c)
sf
where
A is the effective area of curved surface of the spherically curved transducer;
ρ is the (mass) density of the medium;
c is the speed of sound in the medium (usually water).
Note 2 to entry: The reciprocity parameter is expressed in watts per pascal squared (W/Pa ).
3.16
p
reference acoustic pressure
product of the uniform normal particle velocity on the spherically curved surface of the
transducer and the characteristic impedance of the medium
Note 1 to entry: Reference acoustic pressure is expressed in pascals (Pa).
3.17
reversible transducer
transducer capable of acting as a projector as well as a receiver
[SOURCE: IEC 60565:2006, 3.26, modified – In the definition, "hydrophone" has been
replaced with "receiver".]
3.18
self-reciprocity method
transducer calibration method based on the reciprocity principle that uses the received echo
signal from the plane reflector that is set perpendicular to the incident beam axis of the
transducer
3.19
S
I
transmitting response to current
transmitting current response
ratio of the reference acoustic pressure on the radiating surface of a transducer in the free-
field in the absence of interference effects to the current flowing through the electrical
terminals of a projector at a given frequency
Note 1 to entry: Transmitting response to current is expressed in pascals per ampere (Pa/A).
– 12 – IEC TS 62903:2018 IEC 2018
3.20
S
U
transmitting response to voltage
transmitting voltage response
the ratio of the reference acoustic pressure on the radiating surface of a transducer in the
free-field in the absence of interference effects to the exciting voltage of a projector at a
given frequency
Note 1 to entry: Transmitting response to voltage is expressed in pascals per volt (Pa/V).
4 Symbols
a effective half-aperture, effective radius of transducer
A effective area of transducer
c speed of sound in sound propagating medium usually in water
d distance from the centre of the transmitting surface of the transducer to the
reflecting plane of the reflector in the geometric focal plane
f resonant frequency
f central frequency
c
F (= R) geometric focal length
geo
G radiation conductance
G diffraction correction coefficient for spherically curved transducer in free-
sf
field self-reciprocity calibration
h height (depth) at the centre of a spherical segment
I acoustic intensity
I , I exciting current amplitude, effective exciting current
T Trms
I short-circuit current amplitude of the generator
k
I first echo current amplitude
echo
J reciprocity parameter of transducer
J reciprocity parameter of spherically curved transducer
sf
k (= 2π/λ), circular wave number
k ratio of the acoustic pressure at the geometric focus to the reference
m
acoustic pressure on the radiation surface of the transducer
l distance from the centre of receiving surface of the hydrophone to the centre of
the transmitting surface of the transducer along their common axis after
alignment
L pulse-echo sensitivity level
Mpe
M free-field voltage sensitivity (receiving voltage response) of a spherically
curved transducer
p reference acoustic pressure of a radiating surface
P acoustic output power
P electrical input power
e
q (=(1 + cosβ)/2), ratio of the true time-average intensity I to the time-average
derived intensity I at the geometric focus
p
Q mechanical quality factor
m
r amplitude reflection coefficient
r (β) average amplitude reflection coefficient on a plane reflector in the geometric
av
focal plane in water for a spherically curved transducer
R radius of curvature
S transmitting response to current
I
S transmitting response at geometric focus to current
If
S transmitting response to voltage
U
S transmitting response at geometric focus to voltage
Uf
∆t acoustic pulse transit time
F
U open-circuit voltage amplitude of tone burst generator
U , U exciting voltage amplitude, exciting effective voltage of the transducer
T Trms
U maximum of the first echo voltage amplitude received by the transducer to be
calibrated in self-reciprocity calibration process
U output voltage of the current probe picked up the exiting current of the
IT
transducer
U output voltage of the current probe picked up the first echo current of the
Iecho
transducer
U output voltage of the current probe picked up the short-circuit current of the
Ik
tone burst generator
U effective voltage
rms
v particle velocity
w –3 dB beamwidth on geometric focal plane
w –6 dB beamwidth on geometric focal plane
Y electric admittance of transducer
T
Z electric output impedance of generator
i
Z electric impedance of transducer
T
α acoustic attenuation coefficient in medium (usually in water)
β (= arcsin(a/R)), focus half-angle
θ electric impedance angle
e
ρ (mass) density of the sound propagating medium (usually water)
η electroacoustic efficiency
a/e
λ wavelength
τ pulse duration
5 General
The transducer characteristics include the ultrasonic field parameters and the transmission
and reception performance parameters.
The focused field performance parameters include the effective half-aperture (the effective
radius), the beam width, the effective area, the geometric focal length, and the focus
half-angle for spherically curved transducers.
The transmission performance parameters include the radiation conductance, the acoustic
output power, the free-field transmitting response to current (voltage), the
electroacoustic efficiency, and the electric impedance.
The reception performance parameter is the free-field voltage sensitivity.
The transmission-reception parameter is the pulse-echo sensitivity level.
In this document, the beam profile method using a hydrophone is defined for the
measurement of the field performance parameters; the self-reciprocity method is defined for
– 14 – IEC TS 62903:2018 IEC 2018
the measurement of the free-field transmitting response to current (voltage), the free field
voltage sensitivity, pulse-echo sensitivity level, and the acoustic output power (see Annex
E); the radiation conductance is derived from the acoustic power and the effective exciting
voltage; the electroacoustic efficiency is calculated from the acoustic output power and the
detected electrical input power. Relations between these electroacoustical parameters are
given in Annex G.
6 Requirements of the measurement system
6.1 Apparatus configuration
The electrical system of the apparatus consists of a tone burst generator, a current monitor
(probe), an oscilloscope and two switches. The acoustical system consists of a water tank for
the measurements, a measurement hydrophone, fixtures, positioning and orientation systems
(for both the transducer and the hydrophone), displacement sensors or indicators, and a
stainless-steel reflector, as shown in Annex F. The apparatus for determining the effective
radius and the self-reciprocity calibration are shown in Figures F.1 and F.2, respectively.
6.2 Measurement water tank
The tank shall have sufficient effective space of water bath to ensure that the maximum
distance between the hydrophone and the transducer can be achieved to meet the
requirements for fixtures, positioning and orienting the devices. The minimum dimensions of
the tank for the tone burst field measurement only should be
2 2 1/2 2 2 1/2
(R + cτ) × (2Rcτ + c τ ) × (2Rcτ + c τ ) (length × width × height), where R is the radius of
curvature, c is the speed of sound in water, τ is the pulse duration and less than or equal to
30 cycles. Considering other requirements the tank should be not smaller than
0,55 m × 0,32 m × 0,38 m (length × width × height). The tank is filled with degassed water,
and the water temperature is indicated by a thermometer.
6.3 Fixturing, positioning and orientation systems
The transducer and the hydrophone shall be fixed on fixtures that allow positional adjustment
of the devices in three perpendicular directions as well as allowing their angles of azimuth
and elevation to be independently and continuously being adjusted. The positioning accuracy
should be better than ±0,1 mm in the axial direction z and ±0,01 mm in the lateral directions x
and y, while the orientation accuracy should be better than ±0,05°. The resolution of the
displacement sensor should be 0,01 mm or less.
6.4 Reflector
The reflector is a thick plate or cylinder made of stainless steel. One of the planes or terminal
surfaces of the reflector is used as a reflection plane that should be flat to ±10 μm and should
also show a surface finish good to ±5 μm. The thickness of the reflector shall be large enough
to ensure that the first echo from the rear surface does not interfere with that from the front
surface at the lowest frequency used. The reflector diameter shall be sufficient to reflect the
entirety of the ultrasonic beam energy. The reflector diameter should be at least twice the
−26 dB beam width or greater than the aperture of transducer whichever is the greater. The
average amplitude reflection coefficient r (β) is almost a constant 0,973 at the interface
av
between water and stainless steel when the focus half-angle β is less than 13°. For other β
values, r (β) can be picked up from the data of Table A.2 in Annex A.
av
6.5 Current monitor (probe)
The frequency response of the current sensitivity of the monitor should be constant up to
1,4 times of the frequency of the current to be measured. The maximum detectable current
should be greater than 1,5 times of the current to be measured. The rise time should be
shorter than or equal to 20 ns. The accuracy should be better than or equal to ±1 %.
6.6 Oscilloscope
The bandwidth of the oscilloscope should be greater than or equal to 70 MHz. The resolution
of voltage should be better than 1 mV. The error of voltage measurement should be less than
or equal to ±2 %.
6.7 Measurement hydrophone
The maximum radius a of the hydrophone active element should satisfy Formula (1):
h,max
l
2 2
a = l + a (1)
h,max
8 a
where l is the distance between the hydrophone and the transducer, a is the effective half-
aperture of the transducer, and λ is the wavelength. The hydrophone used for the procedure
does not need to be calibrated.
7 Measurement of the effective half-aperture of the spherically curved
transducer
7.1 Setup
The transducer and the hydrophone are arranged in the water tank as shown in Figure F.1. A
tone burst generator is used to excite the transducer directly or using a matching network.
The hydrophone is used to detect the acoustic pressure in the field. The oscilloscope is used
to detect the exciting voltage of the transducer, the output voltages of the hydrophone and the
current monitor.
7.2 Alignment and positioning of the hydrophone in the field
IEC 61828:2006 is the measurement guideline of this section. Only the geometric focal
length is used in this document.
Firstly, the exciting voltage and frequency of the transducer shall remain constant. Then, the
maximum sensitivity direction of the hydrophone shall be aligned with the beam axis of the
transducer to maximize the output voltage of the hydrophone. In the third step, the axial
distance between the hydrophone and the transducer along the beam axis shall be adjusted
to make the acoustic pulse transit time ∆t between the transmitted pulse and the directly
F
received pulse of the hydrophone equal to R/c, where R is the radius of transducer surface
curvature, i.e. the geometric focal length, and c is the speed of sound. i.e.
∆t = R/c. (2)
F
Generally, R is known by the designer or manufacturer. c is the speed of sound in water (see
Annex D).
7.3 Measurements of the beamwidth and the effective half-aperture
Scanning of hydrophone along the x axis and the y axis across the geometric focus in the
focal plane (x,y,R) allows two pairs of −3 dB and −6 dB beamwidth (w , w and w , w ) to
3x 3y 6x 6y
be detected, respectively. The effective half-aperture or the effective radius of the transducer
is calculated from the average beamwidths w and w in two directions as
3 6
lR 1,62 2,22
(3)
a = +
2π w w
3 6
where w = (w + w )/2; w = (w + w )/2.
3 3x 3y 6 6x 6y
– 16 – IEC TS 62903:2018 IEC 2018
7.4 Calculations of the focus half-angle and the effective area
The focus half-angle β of the spherically curved transducer is given as follows
β = arcsin(a /R). (4)
The effective area of the spherically curved transducer is given as follows:
A = 2πR (1− cos β ) (5)
8 Measurements of the electroacoustical parameters and the acoustic output
power
8.1 Self-reciprocity method for transducer calibration
8.1.1 Experimental procedures
The transducer and the reflector are arranged in the water tank as shown in Figure F.2. The
working frequency of the tone burst generator is set at a frequency f, and the output voltage is
kept constant. The pulse duration is equal to or less than 30 cycles, and the duty cycle factor
is approximately 1/30. The open-circuit voltage U and the short-circuit current I of the
0 k
generator are detected using the oscilloscope and the current monitor. If U is very large, I
0 k
should not be detected to avoid damage to the generator. The transducer to be measured is
then excited and t
...
SLOVENSKI STANDARD
01-april-1999
9RGQHWXUELQHDNXPXODFLMVNHþUSDONHLQþUSDOQHWXUELQH±5D]SLVQDGRNXPHQWDFLMD
±GHO 6PHUQLFH]DWHKQLþQHVSHFLILNDFLMH3HOWRQRYLKWXUELQ
Hydraulic turbines, storage pumps and pump-turbines - Tendering documents - Part 3:
Guidelines for technical specifications for Pelton turbines
Ta slovenski standard je istoveten z: IEC/TR 61366-3
ICS:
27.140 Vodna energija Hydraulic energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL
IEC
REPORT – TYPE 3
61366-3
First edition
1998-03
Hydraulic turbines, storage pumps
and pump-turbines –
Tendering documents –
Part 3:
Guidelines for technical specifications
for Pelton turbines
Turbines hydrauliques, pompes d’accumulation
et pompes-turbines –
Documents d’appel d’offres –
Partie 3:
Guide des spécifications techniques pour les turbines Pelton
IEC 1998 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http: //www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
V
International Electrotechnical Commission
For price, see current catalogue
– 2 – 61366-3 IEC:1998(E)
CONTENTS
Page
FOREWORD . 4
Clause
0 Introduction to technical specifications . 7
1 Scope. 9
2 Reference documents . 9
3 Technical requirements. 9
3.1 Scope of work. 9
3.2 Limits of the contract . 10
3.3 Supply by Employer . 10
3.4 Design conditions . 11
3.5 Technical performance and other guarantees. 14
3.6 Mechanical design criteria . 17
3.7 Design documentation . 17
3.8 Materials and construction . 18
3.9 Shop inspection and testing . 19
4 Technical specifications for fixed/embedded components. 20
4.1 Manifold . 21
4.2 Turbine housing. 21
5 Technical specifications for stationary/removable components . 22
5.1 Branch pipe (including intake pipe and nozzle pipe). 22
5.2 Upper turbine housing (if not embedded). 22
5.3 Turbine cover . 23
5.4 Brake jet assembly . 23
6 Technical specifications for injector/deflector system . 23
6.1 Injector system . 23
6.2 Deflector system. 24
7 Technical specifications for rotating parts, guide bearings and seals . 24
7.1 Runner . 24
7.2 Main shaft . 25
7.3 Turbine guide bearing. 25
7.4 Main shaft seal (if necessary) . 25
7.5 Standstill maintenance seal (if necessary). 26
61366-3 © IEC:1998(E) – 3 –
Clause Page
8 Technical specifications for thrust bearing (when specified as part of the
hydraulic machine). 26
8.1 Design data . 26
8.2 Bearing support . 26
8.3 Bearing assembly . 26
8.4 Oil injection pressure system . 27
9 Technical specifications for miscellaneous components . 27
9.1 Walkways, access platforms and stairs . 27
9.2 Lifting fixtures. 27
9.3 Special tools. 27
9.4 Standard tools . 27
9.5 Turbine pit hoist. 27
9.6 Nameplate. 27
9.7 Runner cart and rails (if required) . 28
9.8 Access door to turbine housing interior (if required). 28
10 Technical specifications for auxiliary systems. 28
10.1 Bearing lubrication system . 28
10.2 Cooling water system for runner. 28
10.3 Tailwater air admission system . 28
10.4 Turbine pit drainage. 28
11 Technical specifications for instrumentation . 29
11.1 Controls. 29
11.2 Indication. 29
11.3 Protection. 29
12 Spare parts. 29
13 Model acceptance tests . 29
14 Site installation and commissioning tests . 30
14.1 General . 30
14.2 Installation procedures. 30
14.3 Tests during installation . 31
14.4 Commissioning tests. 31
15 Field acceptance tests . 31
15.1 Scope and reports . 31
15.2 Inspection of cavitating pitting. 31
– 4 – 61366-3 IEC:1998(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
TENDERING DOCUMENTS –
Part 3: Guidelines for technical specifications
for Pelton turbines
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
report of one of the following types:
• type 1, when the required support cannot be obtained for the publication of an International
Standard, despite repeated efforts;
• type 2, when the subject is still under technical development or where for any other reason
there is the future but no immediate possibility of an agreement on an International
Standard;
• type 3, when a technical committee has collected data of a different kind from that which is
normally published as an International Standard, for example "state of the art".
Technical reports of types 1 and 2 are subject to review within three years of publication to
decide whether they can be transformed into International Standards. Technical reports of
type 3 do not necessarily have to be reviewed until the data they provide are considered to be
no longer valid or useful.
IEC 61366-3, which is a technical report of type 3, has been prepared by IEC technical
committee 4: Hydraulic turbines.
61366-3 © IEC:1998(E) – 5 –
The text of this technical report is based on the following documents:
Committee draft Report on voting
4/110/CDV 4/122/RCV
Full information on the voting for the approval of this technical report can be found in the report
on voting indicated in the above table.
Technical Report IEC 61366-3 is one of a series which deals with Tendering documents for
hydraulic turbines, storage pumps and pump-turbines. The series consists of seven parts:
Part 1: General and annexes (IEC 61366-1)
Part 2: Guidelines for technical specification for Francis turbines (IEC 61366-2)
Part 3: Guidelines for technical specification for Pelton turbines (IEC 61366-3)
Part 4: Guidelines for technical specification for Kaplan and propeller turbines (IEC 61366-4)
Part 5: Guidelines for technical specification for tubular turbines (IEC 61366-5)
Part 6: Guidelines for technical specification for pump-turbines (IEC 61366-6)
Part 7: Guidelines for technical specification for storage pumps (IEC 61366-7)
Parts 2 to 7 are "stand-alone" publications which when used with Part 1 contain guidelines for a
specific machine type (i.e. Parts 1 and 4 represent the combined guide for Kaplan and
propeller turbines). A summary of the proposed contents for a typical set of Tendering
documents is given in the following table 1 and annex A. Table 1 summarizes the arrangement
of each part of this guide and serves as a reference for the various chapters and sections of
the Tendering documents (see 3.2 of this part).
A bilingual edition of this technical report may be issued at a later date.
Table 1 – Summary of guide for the preparation of Tendering Documents for hydraulic turbines, storage pumps and pump-turbines
CONTENTS OF GUIDE IEC 61366-1 TO IEC 61366-7 SAMPLE TABLE OF CONTENTS OF TENDERING DOCUMENTS (TD)
(Example for the Francis turbines; see 61366-1, annex A)
Part Clause Title Chapter Title
1 General and annexes 1 Tendering requirements
1– 2 Project information
1 1 Object and scope of this guide 3 General conditions
1 2 Reference documents and definitions 4 Special conditions
1 3 Arrangement of Tendering Documents 5 General requirements
1 4 Guidelines for tendering requirements 6 Technical specifications
1 5 Guidelines for project information 6.1 Technical requirements
1 6 Guidelines for general conditions, special conditions and general 6.1.1 Scope of work
requirements 6.1.2 Limits of the contract
6.1.3 Supply by Employer
1 Annexes 6.1.4 Design conditions
6.1.5 Performance and other guarantees
A Sample table of contents of Tendering Documents for Francis turbines 6.1.6 Mechanical design criteria
B Comments on factors for evaluation of tenders 6.1.7 Design documentation
C Check list for tender form 6.1.8 Materials and construction
D Examples of technical data sheets 6.1.9 Shop inspection and testing
E Technical performance guarantees 6.2 Technical specifications for fixed/embedded components
F Example of cavitation pitting guarantees 6.3 Technical specifications for stationary/removable components
G Check list for model test specifications 6.4 Technical specifications for guide vane regulating apparatus
H Sand erosion considerations 6.5 Technical specifications for rotating parts, bearings and seals
6.6 Technical specifications for thrust bearings
2 to 7 Technical specifications 6.7 Technical specifications for miscellaneous components
6.8 Technical specifications for auxiliary systems
2 Francis turbines 6.9 Technical specifications for instrumentation
3 Pelton turbines 6.10 Spare parts
4 Kaplan and propeller turbines 6.11 Model tests
5 Tubular turbines 6.12 Installation and commissioning
6 Pump-turbines 6.13 Field acceptance tests
7 Storage pumps
61366-3 © IEC:1998(E) – 7 –
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
TENDERING DOCUMENTS –
Part 3: Guidelines for technical specifications
for Pelton turbines
0 Introduction to technical specifications
The main purpose of the technical specifications is to describe the specific technical
requirements for the hydraulic machine for which the Tendering documents (TD) are being
issued. To achieve clarity and to avoid confusion in contract administration, the Employer
should not specify anything in the technical specifications which is of importance only to the
preparation of the tender. Such information and instructions should be given only in the
Instructions to Tenderers (ITT). Accordingly, the ITT may refer to other chapters and sections
the Tendering documents but not vice versa. As a general rule the word "Tenderer" should be
confined in use only to TD chapter 1 "Tendering requirements"; elsewhere the term
"Contractor" should be used.
Special attention should be given to items of a project specific nature such as materials,
protective coating systems, mechanical piping systems, electrical systems and instrumentation.
It is common for the Employer to use technical standards for such items which would apply to
all contracts for a particular project or projects. In this event, detailed technical standards
should be specified in TD chapter 5 "General requirements".
Technical specifications for the various types of hydraulic machines included in this guide are
provided in the following parts:
– Francis turbines (Part 2);
– Pelton turbines (Part 3);
– Propeller and Kaplan turbines (Part 4);
– Tubular turbines (Part 5);
– Pump-turbines (Part 6);
– Storage pumps (Part 7).
The guidelines for preparation of Pelton turbine specifications include technical specifications
for the following:
– Design conditions: Project arrangement, hydraulic conditions, specified conditions, mode of
operation, generator characteristics, synchronous condenser characteristics, transient
behaviour data, stability of the system, noise, vibration, pressure fluctuations and safety
requirements.
– Technical performance and other guarantees:
ypower;
ydischarge (if required);
yefficiency;
ymaximum momentary pressure;
yminimum momentary pressure;
ymaximum momentary overspeed;
ymaximum steady-state runaway speed;
– 8 – 61366-3 © IEC:1998(E)
ycavitation pitting;
yhydraulic thrust;
ymaximum weights and dimensions for transportation, erection and maintenance.
– Mechanical design criteria: design standards, stresses and deflections and special design
considerations (earthquake acceleration, etc.).
– Design documentation: Contractor’s input needed for the Employer's design, Contractor's
drawings and data, Contractor's review of the Employer's design and technical reports by
Contractor.
– Materials and construction: material selection and standards, quality assurance procedures,
shop methods, corrosion protection and painting.
– Shop inspection and testing: general requirements and reports, material tests and
certificates, dimensional checks, shop assembly and tests.
– Fixed/embedded components: manifold for multi-jet turbines and turbine housing.
– Stationary/removable components: branch pipe for horizontal turbines, upper turbine
housing (if not embedded), turbine cover, brake jet assembly).
– Injector and deflector systems: nozzles, needles, needle servomotors, deflectors or cut-in
deflectors, deflector servomotors, links, needle-deflector combining mechanism and oil
piping.
– Rotating parts, bearings and seals: runner, main shaft, guide bearing with oil supply,
oil/water cooler, shaft seal.
– Thrust bearing (when part of the hydraulic machine supply): bearing support, thrust block,
rotating ring, thrust bearing pads and pivots, oil sump with oil supply (common with guide
bearing, if any), oil/water coolers, instrumentation.
– Miscellaneous components: walkways, lifting fixtures, special tools, standard tools, turbine
pit hoist, nameplate, runner inspection platform (if required).
– Auxiliary systems: bearing lubrication system (if required), tailwater air admission system,
turbine pit drainage (if required), turbine housing ventilation, tailwater depression (if
required).
– Instrumentation: controls, indication and protection.
– Spare parts: basic spare parts.
– Model acceptance tests: test requirements.
– Site installation and commissioning tests: Installation procedures and commissioning tests.
– Field acceptance tests: scope of field tests, reports and inspection of cavitation pitting.
An example of the proposed table of contents for Tendering documents for a Francis turbine is
given in annex A of IEC 61366-1. The example does not include technical specifications for the
control system, or high-pressure side valves which, at the Employer’s option, may be included
in the Tendering documents for the Pelton turbine or may be specified in separate Tendering
documents.
Chapter 6 (technical specifications) of the Tendering documents should be arranged as follows:
6.1 Technical requirements;
6.2 Technical specifications for fixed/embedded components;
6.3 Technical specifications for stationary/removable components;
6.4 Technical specifications for deflector/cut-in deflector regulating apparatus;
6.5 Technical specifications for rotating parts, guide bearings and seals;
6.6 Technical specifications for thrust bearing;
6.7 Technical specifications for miscellaneous components;
6.8 Technical specifications for auxiliary systems;
6.9 Technical specifications for instrumentation;
61366-3 © IEC:1998(E) – 9 –
6.10 Spare parts;
6.11 Model acceptance tests;
6.12 Site installation and commissioning tests;
6.13 Field acceptance tests.
1 Scope
This Technical Report, referred to herein as “Guide”, is intended to assist in the preparation of
Tendering documents and Tendering proposals and in the evaluation of tenders for hydraulic
machines. This part of IEC 61366 provides guidelines for Pelton turbines.
2 Reference documents
IEC 60041:1992, Field acceptance tests to determine the hydraulic performance of hydraulic
turbines, storage pumps and pump-turbines
IEC 60193:1965, International code for model acceptance tests of hydraulic turbines
IEC 60308:1970, International code for testing of speed governing systems for hydraulic
turbines
IEC 60545:1976, Guide for commissioning, operation an maintenance of hydraulic turbines
IEC 60609-2:1997, Cavitation pitting evaluation in hydraulic turbines, storage pumps and
pump-turbines – Part 2: Evaluation in Pelton turbines
IEC 60994:1991, Guide for field measurement of vibrations and pulsations in hydraulic
machines (turbines, storage pumps and pump-turbines)
IEC 60995:1991, Determination of the prototype performance from model acceptance tests of
hydraulic machines with consideration of scale effects
1)
IEC 61362, Guide to specification of hydro-turbine control systems
ISO 3740:1980, Acoustics – Determination of sound power levels of noise sources – Guidelines
for the use of basic standards and for the propagation of noise test codes
3 Technical requirements
3.1 Scope of work
This subclause should describe the scope of work and the responsibilities which are to be
2)
conferred upon the Contractor. The general statement of scope of work presented in TD
section 2.1 (5.1) shall be consistent with what is presented here. In a similar manner, pay items
in the tender form, TD section 1.2 (subclause 4.2) should be defined directly from TD
subsection 6.1.1.
The scope of work should begin with a general statement which outlines the various elements
of the work including (where applicable) the design, model testing, supply of materials and
labour, fabrication, machining, quality assurance, quality control, shop assembly, shop testing,
spare parts, transportation to site, site installation, commissioning, acceptance testing,
warranty and other services specified or required for the items of work. The general statement
should be followed by a specific and detailed list of the major items which the Employer wishes
to have as separate payment items in the tender form, for example:
___________
1)
To be published.
2)
All references to Tendering documents (TD) apply to annex A of IEC 61366-1.
– 10 – 61366-3 © IEC:1998(E)
Item Description
1 Two (2) vertical shaft Pelton type hydraulic turbines each with a specified power of not
less than 180 000 kW under a specified specific hydraulic energy of 11 500 J/kg
(specified head of 1 172 m);
2 Turbine model testing;
3 Tools, slings and handling devices required for maintenance of the turbines;
4 Transportation and delivery to site;
5 Site installation, commissioning, and acceptance testing of the turbines;
6 Preparation and submission of operation and maintenance manual and training of
Employer's operating and maintenance staff in the optimum use of these manuals; and
7 Spare parts required for operation and maintenance.
3.2 Limits of the contract
This subclause, making reference to Employer's drawings and data, should describe the limits
of the contract considering the following:
– details of the design and supply limits of the high and low-pressure sides of the machine;
– details, location, and responsibility for field connection of manifold/branch pipe to penstock
or valve on high-pressure side;
– details and location of the downstream termination of the turbine housing (including
inspection platform, if required);
– details and location of gate(s) on low-pressure side (if required);
– orientation and location of turbine/generator shaft flange interface;
– responsibility for supply and installation of flange coupling bolts, nuts and guards at
generator/turbine coupling, including drilling jig;
– responsibility for supply and installation of bolts, nuts, gaskets at piping terminations;
– termination of governor piping;
– termination of manifold dewatering piping;
– termination of manifold or branch pipe air exhaust piping (if any);
– termination of pit drainage piping (if required);
– termination of bearing lubricating oil piping (if required);
– termination of shaft seal piping (if specified);
– termination of cooling water piping for bearings;
– turbine mounted thrust bearing (if desired);
– termination points and junction boxes for wiring for power, control, indication, protection,
and lighting;
– compressed air for service and other functions.
NOTE – Contract limits will change if other major items of equipment (such as hydro-turbine control systems,
valves, gates, generators, excitation systems, control metering and relaying systems, switchgear, and power
transformers) are included with the hydraulic machine in a common set of Tendering documents.
3.3 Supply by Employer
This subclause should be complementary to 5.6 of IEC 61366-1 (TD section 2.6) and should
list the items and services which will be the responsibility of the Employer. The following items
should be considered:
– services during site installation and testing;
– temporary enclosures for site storage of turbine parts or for erection;
61366-3 © IEC:1998(E) – 11 –
– installation in primary concrete of small items provided by the Contractor, such as anchors,
sole plates, and piping;
– concrete for embedment of turbine components-supply, placement and controls, including
monitoring and verification during and after concrete placement by others;
– grout injection, if required, either within or around turbine components;
– powerhouse crane and operator;
– connections to powerhouse air, oil and water piping systems;
– supply of filtered water for turbine shaft seal (if by Employer);
– electrical wiring and hardware external to specified termination points;
– electric motor starters and controls;
– control, annunciation and protection systems external to specified termination points;
– external lubricating oil storage, distribution, and purification systems;
– lubricants, bearing and governor oil to the Contractor's specifications.
It should be stated that any materials or services required for installation and commissioning of
the units, and not specifically mentioned in the above list of the Employer supplied items and
services are to be provided by the Contractor under contract.
3.4 Design conditions
3.4.1 Project arrangement
The project arrangement should contain the Employer's detailed description together with
general arrangement drawings (by the Employer) of the powerhouse and waterways at the low
and high-pressure sides including channels, galleries, penstocks, surge tanks, gates, valves,
etc. The description should be an extension of the applicable data provided in TD chapter 2
"Project information". The data shall be sufficiently clear so that the Contractor is aware of
physical conditions which may influence its detailed design.
In any event, the Employer should retain responsibility for specifying values of all parameters
on which guarantees are based, as part of the overall design of the plant. This applies
particularly to the correct inlet and outlet conditions and in co-ordination of the interaction
between the hydraulic machine and the waterways.
3.4.2 Hydraulic conditions
This subclause should present the hydraulic conditions under which the Employer proposes to
operate the completed facility such as:
– range of specific hydraulic energy (head) of the plant;
– specific hydraulic energy losses between headwater level and high-pressure reference
section of the machine (E );
L 3-1
– specific hydraulic energy (head) of the machine (see subclause 2.5);
– headwater levels, maximum, minimum and normal and when no water is flowing;
– tailwater levels, maximum, minimum and normal, and when no water is flowing;
– tailwater level as a function of discharge;
– power or discharge values in the range of specific hydraulic energy (head);
– maximum specific hydraulic energy (head) for runaway speed guarantee;
– range of water temperatures;
– water quality analysis (chemical, corrosive nature, biological, and suspended solids);
– range of ambient (interior and exterior) temperatures and humidity (tropical environment or
extreme cold needs to be clearly defined).
– 12 – 61366-3 © IEC:1998(E)
3.4.3 Specified conditions
a) Modes of operation: As an extension to TD section 2.5, the Employer should provide
sufficient data to enable the Contractor to understand the Employer's intended mode(s) of
operation, e.g. base load or peaking. Data should include, wherever possible, the
anticipated number of start-stops per year and the capacity factor of the plant. Special
operating uses shall also be clearly identified such as synchronous condenser, spinning
reserve, isolated and black start operations and requirements, waterway/penstock draining-
through turbine.
b) Power (P), Specific Hydraulic Energy (E) [Head (H)], and Discharge (Q): The specified
specific hydraulic energy (head) and discharge of the machine are determined from an
analysis of available discharge, specific hydraulic energy (head) of the plant and hydraulic
losses external to the machine with respect to statistical duration (refer to 2.3 to 2.6 of
IEC 61366-1). The relevant power can be established from a predetermined value of
efficiency.
If the range of specific hydraulic energy (head) is wide, more than one specified value for E,
Q and P may need to be selected to define the operational range of the machine.
In the case of an unregulated turbine and if there are any limitations on maximum discharge
at any specific hydraulic energy (head), the Employer shall provide adequate data in the
technical specifications to enable the Contractor to optimize turbine design while respecting
these limitations.
c) Speed: The choice of speed of the unit has an impact on turbine, generator costs and
powerhouse costs. The choice of speed may be influenced by strength considerations.
Reduced turbine efficiency and cavitation may be introduced by increasing speed beyond a
certain limit.
In most cases, the project schedule dictates an early decision with respect to speed. Under
such conditions, discussions should be held with potential suppliers of turbines and
generators to fix a preferred speed; alternative proposals may be invited in the ITT.
d) Direction of rotation: The direction of rotation of the turbine is dictated by the optimum
orientation of the manifold pipe with respect to intake, penstock and powerhouse costs. The
direction should be specified clockwise or counter-clockwise looking from the generator
toward the turbine.
3.4.4 Generator characteristics
The specifications should state the principal characteristics of the generators to which the
turbines will be coupled, for example:
– capacity (kVA);
– power factor;
– frequency (normal and exceptional range);
– inertia or flywheel effect of generator;
– preferred speed (if established);
– preferred bearing arrangement (if established);
– approximate diameter of rotor (if available).
3.4.5 Transient behaviour data
The Employer should, during preliminary design phase of the project and prior to turbine
selection, determine the various factors relating to power acceptance and power rejection by
the turbine. These factors may include:
– acceptable variation in electrical system frequency;
– inertia of the rotating parts or mechanical starting time;
– details of high-pressure conduit for the turbine, including surge tank, if used;
61366-3 © IEC:1998(E) – 13 –
– water starting time;
– velocity of pressure wave (sound velocity in the water passages);
– turbine needle opening and closing times;
– high-pressure side valve/gate opening and closing time;
– transient pressure variations in the turbine manifold/branch pipe and penstock;
– transient water level variations in the turbine housing;
– pressure fluctuations at high-pressure side of turbine.
Transient data established by the Employer should be provided and those data which require
verification by the Contractor should be specified. Other data not specified by the Employer
may have to be established by the Contractor. (Refer to guarantees in subclauses 3.5.5 and
3.5.6).
3.4.6 Stability of the system
The hydro-turbine control system should be specified in accordance with IEC 61362. The
performance of the hydro-turbine control system should be specified in accordance to
IEC 60308. The Employer should furnish the information necessary to predict possible
resonance in the water passages of the power plant and in the unit. Admissible limits may be
specified for fluctuation of turbine shaft torque.
3.4.7 Noise
Noise level limits may be legislated by national or local statutes. Noise abatement measures
may be the combined responsibility of the Employer and the Contractor. Reference should be
made by the Employer to ISO 3740 together with other standards, statutes or guides to
establish noise level measurement and acceptance criteria. The limits and the means by which
they can be achieved should be specified in TD subsection 6.1.4.7.
NOTE – The Employer should be aware that any additional protection to reduce noise level may have a substantial
effect on the cost of the machine.
3.4.8 Vibration
The specifications should require that the machine operates through its full range of specified
conditions without vibration which would be detrimental to its service life. Reference should be
made by the Employer to IEC 60994 together with other standards or guides to establish
deflection measurements and acceptance criteria. In any event, limits of vibration may be
established for steady-state conditions and for normal transient regimes as criteria for final
acceptance.
3.4.9 Sand erosion considerations
Risk of sand erosion may influence the design and operation of the hydraulic machine. In this
event, the technical specifications should indicate the content of suspended solids, their type,
hardness, size and shape. See IEC 61366-1, annex H.
3.4.10 Safety requirements
The Employer should state specific safety requirements which shall be met in the design of the
turbine. These requirements are in addition to the general safety related items outlined in 5.6 of
IEC 61366-1.
– 14 – 61366-3 © IEC:1998(E)
3.5 Technical performance and other guarantees
3.5.1 General
Hydraulic performance guarantees for hydraulic machines are presented in clause 3 of
IEC 60041. The main guarantees to be specified are outlined in IEC 61366-1, annex E and
should be read in conjunction with IEC 60041.
The main steady-state hydraulic performance guarantees (i.e. power, discharge, efficiency and
runaway speed) may be verified by field acceptance tests or by model tests. Guarantees may
be referred directly to the hydraulic performance of the prototype computed from model tests
with allowance for scale effects or to the hydraulic performance of the model (without scale
effects). Refer to IEC 60193.
The Employer should establish and specify the parameters on which the performance
guarantees are to be based. These parameters include plant specific hydraulic energy (plant
head) and energy losses external to the high-pressure reference section of the machine. The
Employer should retain responsibility for specifying acceptable inlet and outlet conditions of the
machine and for co-ordinating the study of the interaction between the machine and the
external waterways under transient and steady-state oscillating conditions.
In those cases where it is not possible to perform field acceptance tests under specified
conditions, refer to IEC 60041.
The Employer should specify measurement methods and measurement uncertainties which are
contractually applied if different than those established by relevant IEC publications.
In addition to specifying the guaranteed performance provisions in the technical specification, it
is important that the Employer summarize these provisions in TD subsection 1.1.13 of the ITT.
Also, it is desirable that the manner in which Tenderers present and state their performance
guarantees be clearly specified.
The Employer should select the appropriate level and type of performance guarantees for the
machine taking into consideration the intended mode of operation and the importance of the
machine in the electrical system.
When it is necessary to include other aspects of the machine under performance guarantees
(such as stability, noise, and vibration). The Employer should include these provisions at the
end of this clause taking into consideration that available data may not be sufficient based on
extended experience. In any event, conditions under which guarantees are evaluated shall be
specified.
3.5.2 Guaranteed power
In specifying the guarantee for power, refer to TD subsection 6.1.4.3 of Specified conditions
(see IEC 61366-1, annex A), and state clearly the basis of the guarantee. It is necessary in this
subclause, to establish the contractual obligations of the Contractor if the guaranteed power is
not met. The method(s) of measurements, method of comparison with guarantees and
application of IEC 60041 shall be defined.
3.5.3 Guaranteed minimum discharge
It is normally not necessary to specify a particularly low, continuous and stable discharge
guarantee for Pelton turbines. This may, however, be considered in cases of sand erosion. the
Employer should indicate the expected duration of operation and any special discharge
conditions. The method of measurement should be specified.
61366-3 © IEC:1998(E) – 15 –
3.5.4 Guaranteed efficiency
The Employer shall establish and specify:
a) Basis of guarantee; model or prototype.
b) Method proposed to measure guaranteed efficiency
– by field acceptance tests of one or more prototype turbines (see IEC 60041),
– by model acceptance tests in the Contractor's laboratory or in another laboratory
acceptable to both parties using test results with a mutually agreed step-up formula
(see IEC 60193).
c) Efficiency weighting formula to allow the Tenderer to optimize the guaranteed efficiency in
the normal operating range of the turbine with respect to both power and specific hydraulic
energy (head) while taking into consideration the value specified by the Employer for gain
or loss in efficiency.
d) Applicable codes (see 2.1 of this guide).
e) Measurement methods and preliminary estimated measurement uncertainties to be
contractually applied if different than those established by relevant IEC publications.
f) Contractual consequences, if any, of the Contractor's failure to fulfil the guaranteed
efficiency or of the Contractor exceeding its guaranteed efficiency (penalty or premium).
The technical data sheets (IEC 61366-1, annex D) of the tender forms should provide space for
Tenderers to record the guaranteed weighted efficiency.
In large multi-unit projects which justify the expense, the Employer may choose to preselect
two or more competing Tenderers for the performance of turbine model tests at the Employer's
expense. In this event, results of the model tests can be used in the final award of the contract
to the successful Tenderer.
3.5.5 Guaranteed maximum/minimum momentary pressure
It is usual for the Contractor to guarantee momentary pressure even when there is no
contractual responsibility for complete design of the plant. (Refer to annex E, E.2.6). The
Contractor should be required to calculate and guarantee the maximum momentary pressure
under load rejection from specified conditions (specified power and specified specific hydraulic
energy) and under the most unfavourable transient conditions established by the Employer.
However, the Employer shall specify all relevant data because of the involvement and influence
of the electrical generator, speed regulator, and waterway system in the transient phenomenon
(see 3.4.5).
3.5.6 Guaranteed maximum momentary overspeed
The maximum momentary overspeed is the overspeed attained under the most unfavourable
transient conditions. Under certain conditions, it may exceed maximum steady-state runaway
speed. The maximum momentary overspeed should be guaranteed by Contractor. However,
the Employer shall specify all relevant data because of the involvement and influence of the
electrical generator, speed regulator, and waterway system in the transient phenomenon
(see 3.4.5).
3.5.7 Guaranteed maximum steady-state runaway speed
The specifications should require that the Contractor guarantee the maximum steady-state
runaway speed under the worst combination of conditions established by the Employer, for
example, maximum specific hydraulic energy (head) and physical maximum needle opening on
the turbine and the worst combination of nozzles in operation. Taking into consideration
powerhouse arrangement, number and type of independent shut-off devices, local or remote
control and type of control and protection systems, the specifications should state the duration
for which the unit shall be capable of functioning at maximum steady-state runaway speed. The
duration may vary from a few minutes to several hours at this speed, but the design of the plant
– 16 – 61366-3 © IEC:1998(E)
should keep this duration to a minimum. The guarantee should be stated in the technical data
sheets submitted by Tenderers.
NOTE – It is recommended not to specify or to conduct steady-state runaway speed tests at site. If it is mutually
agreed to conduct such tests, they should be performed at reduced specific hydraulic en
...
Frequently Asked Questions
IEC TS 62903:2018 is a technical specification published by the International Electrotechnical Commission (IEC). Its full title is "Ultrasonics - Measurements of electroacoustical parameters and acoustic output power of spherically curved transducers using the self-reciprocity method". This standard covers: IEC TS 62903:2018, which is a Technical Specification, a) establishes the free-field convergent spherical wave self-reciprocity method for ultrasonic transducer calibration, b) establishes the measurement conditions and experimental procedure required to determine the transducer's electroacoustic parameters and acoustic output power using the self-reciprocity method, c) establishes the criteria for checking the reciprocity of these transducers and the linear range of the focused field, and d) provides guiding information for the assessment of the overall measurement uncertainties for radiation conductance. This document is applicable to: i) circular spherically curved concave focusing transducers without a centric hole working in the linear amplitude range, ii) measurements in the frequency range 0,5 MHz to 15 MHz, and iii) acoustic pressure amplitudes in the focused field within the linear amplitude range.
IEC TS 62903:2018, which is a Technical Specification, a) establishes the free-field convergent spherical wave self-reciprocity method for ultrasonic transducer calibration, b) establishes the measurement conditions and experimental procedure required to determine the transducer's electroacoustic parameters and acoustic output power using the self-reciprocity method, c) establishes the criteria for checking the reciprocity of these transducers and the linear range of the focused field, and d) provides guiding information for the assessment of the overall measurement uncertainties for radiation conductance. This document is applicable to: i) circular spherically curved concave focusing transducers without a centric hole working in the linear amplitude range, ii) measurements in the frequency range 0,5 MHz to 15 MHz, and iii) acoustic pressure amplitudes in the focused field within the linear amplitude range.
IEC TS 62903:2018 is classified under the following ICS (International Classification for Standards) categories: 17.140.50 - Electroacoustics; 27.140 - Hydraulic energy engineering. The ICS classification helps identify the subject area and facilitates finding related standards.
IEC TS 62903:2018 has the following relationships with other standards: It is inter standard links to IEC TS 62903:2023. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase IEC TS 62903:2018 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of IEC standards.
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